TY  - EJOU
AU  - Polezhaev, Denis 
AU  - Vjatkin, Alexey 
AU  - Kozlov, Victor 

TI  - Effect of Libration on Fluid Flow and Granular Medium Dynamics in a Rotating Cylindrical Annulus
T2  - Fluid Dynamics \& Materials Processing

PY  - 2025
VL  - 21
IS  - 5
SN  - 1555-2578

AB  - The dynamics of fluid and non-buoyant particles in a librating horizontal annulus is studied experimentally. In the absence of librations, the granular material forms a cylindrical layer near the outer boundary of the annulus and undergoes rigid-body rotation with the fluid and the annulus. It is demonstrated that the librational liquefaction of the granular material results in pattern formation. This self-organization process stems from the excitation of inertial modes induced by the oscillatory motion of liquefied granular material under the influence of the gravitational force. The inertial wave induces vortical fluid flow which entrains particles from rest and forms eroded areas that are equidistant from each other along the axis of rotation. Theoretical analysis and experiments demonstrate that a liquefied layer of granular material oscillates with a radian frequency equal to the angular velocity of the annulus and interacts with the inertial wave it excites. The new phenomenon of libration-induced pattern formation is of practical interest as it can be used to control multiphase flows and mass transfer in rotating containers in a variety of industrial processes.
KW  - Fluid; granular medium; rotation; librations; inertial waves; pattern formation

DO  - 10.32604/fdmp.2025.062000